Identical? Have you ever heard the expression "not always right, but never in doubt"?

What should the following show?

var f = function () {
};

function g() {
}
alert(f.name == g.name);

By any ordinary sense "identical", you'd think it would pop-up "true", but lo, f.name is undefined but g.name is "g".

The function pointed to by f is anonymous in the sense that it does not know its own name, although other functions may have a name for it (indeed, it any function does not appear somewhere in the namespace, it's unreferenced and so, can never be called and will be cleaned up by the GC.

In both cases you are assigning a function to a named variable in a given namespace. The biggest difference is the semicolon at the end of the first example, but for your consideration the difference is whether the namespace assignment is implicit to a command or explicitly stated. An anonymous function is a function not assigned to a name. This is an example of an anonymous function:

I ve typically used the keyword function to denote that I m creating a function. In quick testing, I find no way to call a function with the keyword

Message 3 of 19
, May 3, 2010

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I've typically used the keyword 'function' to denote that I'm creating a function. In quick testing, I find no way to call a function with the keyword 'function' present ... short of creating a Function.doit = function () {... which just seems silly, and no way to create a function called 'function' without similar pain. Is there a way to invoke a function with the 'function' keyword present? What's an (albeit likely horrid) example where one could get confused between creation and invocation due to similar syntax?

>Is there a way to invoke a function with the 'function' keyword present?

(function (foo) {
return foo;
})('bar');

--
Noah Sussman
Software Historian
@noahsussman

A foolish consistency is the hobgoblin of little minds
-- Emerson

Rob Richardson

You re creating it with function then invoking it right away. Is there a similar way to use the keyword function to call a previously defined function?

Message 5 of 19
, May 3, 2010

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You're creating it with 'function' then invoking it right away. Is there a similar way to use the keyword 'function' to call a previously defined function? If not, it seems sufficient to note the keyword 'function' will define a function, and it's absence will invoke it. The presence or absence of a space is helpful, but the convention is recent and seems somewhat contrived. Reading code of those who don't subscribe to it will lead to misunderstanding. It seems the presence of the word 'function' is a much better identifier of the purpose of the statement than the presence of a space before the parens.

You are correct in that a name property is supplied to the second of these two cases. But the types are identical and variable f has an anonymous function assigned to it. Since f is a named variable with a function as its value it is a function that is not anonymous. JavaScript is a lambda language of downward inheritance that allows accidental creation of global variables. With regard to complex instances of inheritance where closures are used across the variance namespace scopes you have to be sure where your variables are defined to prevent collisions, especially with consideration for reuse. The first convention forces strict awareness of variable declaration, because the function must be declared before it can be executed. The second convention supplies no such awareness, which is potentially problematic with regards to instantiation and invocation as closure in complex logic prior described. Fortunately, JSLint is smart enough to throw an error when a function is used before it is declared. Since the two conventions are identical in representation I would suggest only using the one that is not open to abuse from flawed and sloppy programming.

> Identical? Have you ever heard the expression "not always right,
> but never in doubt"?
>
> What should the following show?
>
> var f = function () {
> };
>
> function g() {
> }
> alert(f.name == g.name);
>
>
> By any ordinary sense "identical", you'd think it would pop-up
> "true", but lo, f.name is undefined but g.name is "g".
>
> The function pointed to by f is anonymous in the sense that it does
> not know its own name, although other functions may have a name for
> it (indeed, it any function does not appear somewhere in the
> namespace, it's unreferenced and so, can never be called and will
> be cleaned up by the GC.
>
> M.

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